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Step 7My Specifics: Notes On Tongue Design
The area of the pedicab in front of the footrest gets a LOT of force applied to it: it's the end of a lever with your passengers at the other end.
My first designs bent so much that one actually bottomed out when I tried to brake, which would not have made for a very customer-friendly experience or me-friendly tip.
So, to arrive at the final product pictured, I found a couple of books on car trailer design (specifically, volumes 1 & 2 of M. M. Smith's "Trailers: How To Design & Build"). You can also check out what trailer hitches look like or just reason through some of the key points:
-load is spread between multiple attachment points to trailer
-tubing that bears the full weight of the pedicab is reinforced
-multiple grade 5 bolts secure each part of the tongue
Experiment with design on this part, and let me know what you come up with!
My first designs bent so much that one actually bottomed out when I tried to brake, which would not have made for a very customer-friendly experience or me-friendly tip.
So, to arrive at the final product pictured, I found a couple of books on car trailer design (specifically, volumes 1 & 2 of M. M. Smith's "Trailers: How To Design & Build"). You can also check out what trailer hitches look like or just reason through some of the key points:
-load is spread between multiple attachment points to trailer
-tubing that bears the full weight of the pedicab is reinforced
-multiple grade 5 bolts secure each part of the tongue
Experiment with design on this part, and let me know what you come up with!
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Of course a bolt may snap in a high force collision. Since a pedicab does not go very fast to begin with, it won't be because the cab is unsafe, but because the car/truck crashing into them is at fault. People have the mistaken impression that pedicabs are meant to be as safe as cars. Bzzt! Wrong answer! But thanks for playing.
Pedicabs are meant to be light, enviromentally friendly, comfy alternatives to motorized taxis or walking. Nothing more, nothing less, aside from making sure the cab can withstand the day-to-day usage of it's driver and riders. *NO* pedicab can withstand a 'high force' collision.
That's like saying bicycle helmets are designed to protect you from death. Below 20kph you'll likely fall on your hands and knees. Above 20 kph (like being hit by a car), no cycle helmet in the world is designed to save you. It comes down to skill of the rider or sheer luck of survivability.
"...this is an accident waiting to happen..." if so, then keep the cars off the streets in town! :-)
That's garbage. It's all the matter of choosing the proper grade hardware. Obviously you've never heard of the SAE J429 standard, grade 0 to 8, for bolts.
Bolts hold wheels on to automotive axles for thousands of miles bouncing over dirt roads without shearing off. They hold leaf springs on to frames while resisting hundreds of ft-lbs of shearing force during hard acceleration or deceleration. They hold girders together with millions of tons pressing down on them.